I. Field of the Invention
The present invention relates generally to vehicles, and more particularly to bimodal hauling vehicles convertible from railway to highway use and conversely.
II. Description of the Prior Art
The idea of moving one kind of vehicle on another vehicle is not new in North America. Between 1843 and 1854, canal boats were hauled by cog railroad over mountains from one stream to another. During the 1850s and the 1860s, boats were used to haul supplies, horses and wagons of Westward bound pioneers on inland waterways. On festive occasions, Canadian railroads operated special picnic trains hauling passengers and sleighs that were mounted on flat cars. In the United States, the first railway-highway intermodal operations were termed "piggyback" operations. The early piggyback operations consisted mainly of trains hauling farmers wagons. The first piggyback train began operation in 1885 and hauled 16 wagons on eight flat cars. The distance travelled was 20 miles and the savings in time was substantial. As the service became more well known special cars were built that could haul four wagons each. Passenger service for the owners or drivers of the wagons was furnished in a separate car. The operation only lasted ten years, but it was the beginning of highway-railway intermodal travel in the United States.
The railroad faced two handicaps in competing with motor carriers. First, rail service did not offer the door-to-door pickup and delivery service provided by motor carriers, and second, freight in less than carload quantities needed better packaging for shipment by rail than by motor carrier. Piggyback service was intended to overcome these problems.
In 1926, the Chicago, North Shore and Milwaukee Railroads began hauling railroad-owned highway trailers on flat cars, providing the first modern piggyback service in the United States.
Between 1939 and 1951, the railroads' efforts to expand piggyback service were largely abandoned. The economic pressure on the railroads to increase traffic was greatly relieved by the freight shipments generated by World War II and by the pent-up demand for consumer goods immediately following the end of the war. When the backlog of orders was reduced, rail tonnage again began to decline. Before any action was taken toward increasing piggyback services, however, the Korean War increased the demand for service to such an extent that railroads did not feel it was necessary to explore avenues which might yield additional freight tonnage. When rail freight tonnage began to decline in 1952, and the railroads again became interested in methods of increasing tonnage, the search lead them to reappraisal of piggyback service. During the 1950s, piggyback operations expanded rapidly and by the end of 1959, most of the principal railroads in the United States were providing piggyback service.
Over the years, many methods and designs of piggyback service have been developed. Each, however, is a variation of one of two primary methods. One of these methods involves hauling the complete trailer and the other involves hauling only the trailer body. The Clejan System is representative of a technique for hauling the complete trailer and the New York Central Railroad's Flexi-Van Service is representative of a technique of hauling only the trailer body. The Clejan System uses trailers outfitted with special railroad wheel dollies that ride on rails built into specially fitted flatbed cars. The dollies can be either permanently attached to the trailer or detachable with a pin mechanism. Detachable dollies are put on the trailer using a hydraulic jack to lift the dolly up to the trailer bottom. A pin is used to connect the dolly to the trailer; no tools are needed. The trailer's rear roadway wheels are not detachable. Front dolly wheels are attached by positioning the wheels under the landing gear and securing them with a pin. The invention described herein does not ride on a flatbed car or have dolly wheels in the anterior portion of the trailer. Instead, it rides directly on the railroad tracks, eliminating the need for loading and unloading trailers from a flatbed car.
The New York Central Flexi-Van system uses trailers outfitted with detachable sliding rear roadway wheel assemblies. To detach a roadway wheel assembly, the trailer is backed up to a flatbed car that has a hydraulic turntable built into it. The roadway wheel assembly is released and slid forward before the turntable is hydraulically raised. The turntable mechanism lifts the trailer off of the roadway wheels. The invention described herein, does not use a detachable roadway wheel assembly. Instead, the roadway wheel assembly is slid forward to the middle of the hauling vehicle and a lifting mechanism in the roadway wheel assembly is used to lift the posterior end of the hauling vehicle for installing or removing a railroad wheel bogie. Also, the Flexi-Van system hauls the trailer on a flatbed car while the invention described herein rides directly on the railroad tracks, saving time and money in switching costs.
The search for an easier and less expensive way of carrying more tonnage lead to an innovation in intermodal transportation. In the late 1950s, the Chesapeake and Ohio Railroad developed a bimodal trailer with separate highway and railway axles, called the Rail Van. The Rail Van was designed to ride directly on the highway or the railway. In the late 1970s, a new trailer was designed with a single rail axle and tandem highway axles. This trailer, designed and built for a company called Road Railer, has a set of non-removable railway wheels located between tandem highway axles. To run on the road, the railway wheels are retracted above the highway wheels. Conversely, to run on rails, the railway wheels are extended below the roadway wheels. One major disadvantage of this system is that the railway wheels are heavy and the weight must be carried at all times. This decreases gas mileage and increases the cost of hauling tonnage over the highway. The present invention avoids this disadvantage by using a slidable highway wheel assembly and a removably attached railway wheel bogie. This allows the trailer of the present invention to drop the railway wheels when travelling over the highway, thus, reducing the cost of hauling over the highway.
The Ferrosud, Carro Bimodale System is another bimodal trailer design. It uses a two-axle railway bogie fitted with a locking device to ensure that the bogie and van trailer are correctly joined. On arrival at the road-rail transfer site, the pneumatic suspension of the trailer is used to lift the van body to a height above the rail bogie. The waiting bogie is moved under the van, the van is lowered into position, and the railway braking system is connected. The roadway wheels end up above the railroad track. One, two-axle bogie is used between two trailers with the back of one trailer mounted on one-half of the bogie and the front of another trailer mounted on the other half of the bogie. This system incorporates the advantage of removable bogies. However, in contrast to the present invention, the two-axle bogie used in the Carro Bimodale System is heavy and cannot be securely attached to the posterior end of the trailer for the purpose of lifting the bogie and moving it to a different track. The present invention uses a slidable highway wheel assembly and securely fastens the railway wheel bogie onto the posterior end of the trailer. The trailer can then be moved to various locations at the operator's desire with the bogie attached. This flexibility saves both time and money when positioning cars in the railroad yard.
U.S. Pat. No. 5,009,169, issued to Viens, discloses a rail bogie including a truck having a platform with railway wheels underneath, a fifth wheel and a hooking lock. A self-actuating lift assembly on the bogie is used to raise and hold a tractor or the back of a semi-trailer. Two different bogie designs are used to support and carry a semi-trailer on the railroad track. Neither bogie, however, can be securely attached to the trailer and lifted from the track. The invention described herein uses one type of bogie which can be attached and moved, giving it the flexibility to be moved in a railroad yard. The connecting mechanism in the present invention is also much simpler to use, since it is only a pin and hole arrangement.
U.S. Pat. No. 4,917,020, issued to Wicks, et al., discloses a transition vehicle with roadway wheels and railway wheels. The transition vehicle contains a clamping mechanism to grasp the sidewalls of a trailer being carried. The roadway wheels are raised during rail use by an air spring suspension system. The transition vehicle can be attached to a road vehicle, another rail car or a train engine. The transition vehicle, however, cannot be securely attached to the trailer and the trailer cannot lift the transition vehicle to a different track location. Again, this reduces flexibility. The transition vehicle also, unlike the invention described herein, is used on the anterior portion of the hauling vehicle, between the moving vehicle and the hauling vehicle, not on the posterior portion of the hauling vehicle.
U.S. Pat. No. 4,448,132, issued to Beatty, discloses a convertible railway highway vehicle containing railway wheels and highway wheels. The vehicle uses a number of axles for highway wheels to maximize the load it can carry. The highway wheels are on a liftable axle assembly with a locking mechanism. An airbag spring assembly is used to lift the axle assembly. Unlike the invention described herein, the railway wheels cannot be disconnected during highway use. This adds additional weight during highway use and increases the cost for hauling over the highway.
From the above analysis, it can be seen that the prior art references, individually and as a whole do not disclose a hauling vehicle convertible from highway to railway use and conversely that uses a removably attached railway wheel bogie that can be carried from one location to another and a slidable highway wheel assembly that is used to lift the posterior end of the hauling vehicle for installation and removal of the railway wheel bogie.